Flavour is fine (at long at is isn't at the cost of game play, obviously[1]), but I'd have a hard time arguing that a light counter is flavour. But maybe that's just me.

[1] ... and that's kind of the point here: It does hurt game play... albeit very slightly.

As others have noted, the part on moving during combat is a bit harsh (even as a warrior, one uses ?phase door and looks for good positioning, although mostly before and not during combat). The rest of the analysis is spot-on, though. You can't have one-turn guaranteed escapes via teleports and destruction without also having dangerous one-turn killers. To compensate for this fact, you make escapes either scarce (tlevel, destruction) or with a small probability of landing you in a pack of time hounds and killing you (teleport). These elements of randomness (one-turn off-screen killers and the teleportation lottery) make the risk management game frustrating for a beginner, until they figure out how to deal with them. It is a structural problem that is difficult to fix without changing completely the mechanics and turning Angband into a completely different game (like Sil did, for instance).

(That said, we all like Angband or we wouldn't be here, and the devs are doing an amazing work of keeping it vital, adding new features and improving the existing ones).

I would argue that you don't want to improve either of flavour/realism or gameplay at the expense of the other. Both are essential ingredients, and the aim should be to improve (whatever that means) both.

Angband is many-faceted game, and different aspects appeal to different people. Looking at it purely as a strategic and tactical challenge - a complicated puzzle, essentially - there probably isn't a lot of need for something like the hunger mechanic. But it adds to the sense that you're controlling a character which is descending into a dungeon and fighting monsters - it's a constant reminder that your character is alive (and just be grateful we don't have a defecation mechanic).

All that said, I'm inclined to agree that the "lose fuel" effect of silver jellies is a bit silly. I suspect it's a hangover from the very early days where just getting down a few levels was a challenge, and nobody's really rethought it. I think oil itself is still on the whole worthwhile, but the light radius effect has promise.

I'm about to finish my first mage, after having won with warrior.

This is an issue, IMO. It's practically trivial to win with mage by drawing everything into an ASC and using runes to protect yourself. OTOH, it's almost impossible to kill a greater balrog in an open floor plan. As a warrior, I could do enough damage in a cooridor to get one down, but as a mage, the only way I can beat a greater balrog is by building an ASC. Same goes for most things with high HP that summon at high frequency.

I'd love to play a mage with more flexibility in open floor plans and not feel like I have to retreat into an ASC for every unique I encounter. But most major deep monsters are threats to start summoning like crazy. Lich's, Ainu, Wyrms, etc. Some of these I can kill now within just a cooridor, but I think fundamentally, there's a gameplay element missing here.

A quick note on the light mechanic.
 

FWIW, in my first few tried with a mage, I actually ran out of light once in the dungeon. I assumed the starter torches were enough, and didn't encounter any light sources in the dungeon while resting and recovering my piddly mana to use for magic missile slowly. Next thing I knew... my 5000 turns was up and I was lightless and spell-less and lost in the blackness to die a lonely death.

Yeah, the dynamics of summons in angband are totally broken.

As mentioned elsewhere, the point is that all actions in angband have instantaneous effects, including, crucially, teleportation.* This removes the possibility of tactics from angband combat. If monsters can't kill you instantly, they can't kill you at all. The result is that every threatening monster has to be able to breathe on you for max, cast high powered mana storms, etc. or summon something that can.

Assuming for a moment some series of monster and player nerfs that untangled that situation, you'd then have to look at the exponential nature of summoning. The instantaneous summons combine with summoning summoners to create another broken situation.

*: Except, oddly, word of recall -- so it's clear that from the beginning developers understood the need for limits on teleportation mechanics, but somehow failed to see the importance for other types of teleportation.

The trade-offs and choices differences between classes/races are what make the game interesting. Mages are very fragile for almost the entire game (unless you stubbornly stay at stat gain until con is maxed) so have to take much more care not to get into situations where multiple monsters have LOS. They also don't get the biggest damage dealing spells until late in the game (although the attack wands do quite well). In return they get the best utility spells for controlling the contents of the dungeon and the monsters in order to prepare for fights in the way that benefits them most.

Warriors OTOH can be a bit more cavalier about dealing with groups of monsters.

You could always play against those greater balrogs the same way as one plays the final fight. You can TP the GB away then mass banish the rest. I prefer in fact an open floor plan as a mage against Morgoth: he will spend a lot of turns just walking towards you while you can use those to fire wands/spells. I did this with my last mage, who also had a great Sling of Buckland and rounded pebbles of Holy Might, which did more damage per round than the wands of annihilation did I think.

I would go other way around, make light sources a bit more versatile, lit flasks of oil could cause temporary fire trap that hurts monsters and lit that area, you could drop lit lanterns that keep illuminating that part of the dungeon and so on.

IIRC NPP rogues could create traps that hurt monsters. That is one feature I really wish vanilla angband could have too. Runes that hurt instead of block.

Rogues can set traps in FAangband, I reckon this could "easily" be imported to Angband? ;-)

Regarding light sources, this seems to be mostly a flavor issue, which is quite right in my view. I don't think that I ever run out of light in years, but it did happen during my learning time. (I remember many times stumbeling through the dungeons of Moria, finding my way only by touching the walls ...)
It definitely adds to the gaming atmosphere, if only for newbies.

For your next character, try playing never using an ASC, only use natural terrain. Then you enjoy the tactical challenge of luring a monster into favorable terrain. I agree that ASCs make things boring. But they're not necessary.

That being said, I've had a long history of wanting to refine summoning and summoning mechanics. I think Nick's changes moving towards cone-breath spells finally allows some of this stuff to occur.